Paper feed devices are legion. It is not known how early or in what form the first sheet feeders were put into operation, but a certain degree of sophistication began developing in the late 1940 era and up until the present writing.
Sheet feeding has taken on almost every conceivable means of causing one sheet to separate from a stack and to proceed into a utilization device. The flat feed from a stack into offset duplicators is one well-known illustration. A 1952 U.S. patent issued to inventor Stevenson and assigned to A. B. Dick Corporation, U.S. Pat. No. 2,585,873, is an example.
Inventors have attempted to facilitate good feeding of a single sheet without double feeding by placing the paper stack in almost every conceivable position relative to the feeding device. A vertical machine is shown by the Bell and Howell assignee, Johnson, U.S. Pat. No. 2,626,148, issued in 1953. Feeders have worked from the bottom, from the top, vertically, inclined, flat, and bowed to name some of the variations. Almost every company that has put out a machine requiring sheet feeding has developed one or more varieties. Pitney-Bowes, IBM, Xerox, and Addressograph-Multigraph Corporation are only a few examples. Vacuum feed devices have also become well-known wherein an airflow through a picker finger causes a top sheet to be lifted off a stack and advanced over into the nip of advancing rollers. Three-M Corporation has developed and marketed a "sticky-finger" feed wherein an adhesive pad is tapped on the top sheet and thereby causes the lifting of a top sheet, in the manner of the vacuum feed.
Accordingly, developments in paper sheet feeding have now become specialized for particular applications, rather than broadly new concepts. The present invention is in the realm of belt feed devices in the general category of Kramell et al, U.S. Pat. No. 3,895,791, but more closely related to Strobel of Xerox Corporation, U.S. Pat. No. 3,934,869. Of further interest is Xerox inventor Strange, U.S. Pat. No. 3,768,803.